Folding photovoltaic strip device

ABSTRACT

A folding photovoltaic strip device is provided comprising a plurality of photovoltaic modules joined to form a strip and pleated by flexible, transverse creases so that the device may be stored folded together along the creases, in a compact form, and the creases opened to expose the modules to energizing light. Preferably the creases are permanent to facilitate folding the device for storage, and the ends of the strip may be attached to a casing and a lid in which the strip is to be stored.

FIELD OF THE INVENTION

[0001] This invention relates to a folding photovoltaic strip device.

BACKGROUND OF THE INVENTION

[0002] It has already been proposed in Japanese Publication No.JP363117472A, publication date May 21, 1998, “Portable Solar Bell PowerSource”, N. Yanagihara and Z. Ito, to provide a power source by windinga long, flexible, thin film solar cell onto a winding shaft and storethe wound film in a package.

[0003] It has been proposed in U.S. Pat. No. 5,605,769 dated Feb. 25, 5,1997, “Method and apparatus for supplying electrical energy to batterypowered equipment”, D. J. Toms, wherein electrical energy is suppliedto, for example, a rechargeable battery by unfurling, i.e. unwinding, aflexible, light converting to electrical energy, strip of photovoltaiccells to form a flat surface for exposure to light.

[0004] While these devices are useful, there is a draw back in that,

[0005] i) if the light converting strip is bent to be coiled, to aradius less than 1 inch (2.54 cm) for storage, performance degradationof the strip in the conversion of light will possibly occur, see, forexample, “Lightweight, Flexible, Monolithic Thin—Film Amorphous SiliconModules on Continuous Polymer Substrates”, D. Grimmer, F. Jeffrey, S.Martens and M. Thomas, J. Solar Energy, 1996, Vol. 18, page 210, lastparagraph;

[0006] ii) a light converting strip at minimum coiling diameter of 2inches (5.08 cm) is unduly bulky; and,

[0007] iii) bending the whole lengths of the photovoltaic cells causebending stresses at easily damage portions of them, such as, forexample, bus bars, each time the cells are coiled or uncoiled.

[0008] There is a need for a photovoltaic strip device which, whenstores, is not subjected to bending damage by being furled or coiled,which is capable of being stored in a compact manner, and which need nothave easily damaged portions subjected to damaging bending stresses eachtime the strip is coiled or uncoiled.

SUMMARY OF THE INVENTION

[0009] According to the present invention, there is provided a foldingphotovoltaic strip device, comprising,

[0010] a) a plurality of photovoltaic modules, joined to form the strip,and wherein,

[0011] b) the strip is pleated by transversely extending flexiblecreases to form a series of panels there between, whereby

[0012] i) with the panels folded together in a concertina-like manner bymeans of the creases, the device is stored in a retracted, compact form,and

[0013] ii) with the panels spread out by means of the creases, themodules can be exposed to light that is convertible by the modules toelectrical energy.

[0014] The panels may be essentially flat.

[0015] The flexible creases may be at intermediate positions acrossmodules.

[0016] Each module may be provided with a flexible crease.

[0017] The flexible creases may be spaced at a module length apart fromone another.

[0018] The flexible creases may be spaced with at least one modulebetween each pair of them.

[0019] The device may include diode electrically connected to the deviceand through which an article may be electrically energized by thedevice.

[0020] The flexible creases are preferably permanent creases.

[0021] Preferably, the permanent creases are open creases that, in therelaxed state, expose the modules to light, and, the strip hassufficient stiffness to be compressed to the retracted, compact form.

[0022] In some embodiments of the present invention, the modules arespaced along, and adhere to, a support with exposed portions of thestrip between modules, flexible, permanent crease are provided in atleast some of the exposed portions of the strip.

[0023] Preferably the creases in the exposed portions will spring opento expose the modules to light.

[0024] In other embodiments of the present invention, a casing isprovided for the strip, to which a first end of the strip is attached,and a lid is provided for closing the strip in the casing, and to whicha second end of the strip is attached.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the accompanying drawings which illustrate, by way of example,embodiments of the present invention.

[0026]FIG. 1 is a plain view of unfolded end portions of a photovoltaicstrip device,

[0027]FIG. 2 is a side view in the direction II-II, FIG. 1, with theportions of the strip pleated by creases and the creases partiallyopened, and electrically connected to an electrical power consumingdevice,

[0028]FIG. 3 is an enlarged side view in the direction II-II, FIG. 1,with the portions of the strip pleated in the completed folded state,and

[0029]FIG. 4 is an enlarged similar view of FIG. 2, but a differentembodiment, and party sectioned.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0030] Referring now to FIGS. 1 to 3, there is shown end portions of afolding photovoltaic strip device 1, comprising

[0031] a) a plurality of photovoltaic modules, some of which are shownand designated 2 to 7, joined to form the strip 1, and wherein,

[0032] b) the strip is pleated, as shown in FIGS. 2 and 3, withtransversely extending, flexible creases 9 to 12, along lines XX, FIGS.1 and 2, to form a series of panels 14 to 19, some of which are shownand designated 14 to 19, whereby,

[0033] i) with the panels 14 to 19 folded together in a concertina-likemanner, as shown in FIG. 3, by means of the creases, such as creases 9to 12, the device 1 is stored in a retracted, compact concertina form,and,

[0034] ii) with the panels 14 to 19 spread out, as shown in FIG. 1, bymeans of the crease, such as these designated 9 to 12, the modules, suchas those designated 2 to 7, can be exposed to light that is convertibleby the modules 2 to 7 to electrical energy.

[0035] It would be appreciated that the photovoltaic modules between theend portions shown in FIG. 1 are identical to those shown in the endportions.

[0036] In this embodiment, the photovoltaic modules 2 to 7 are of aknown type which is described in “Lightweight Flexible, MonolithicThin-Film Amorphous Silicon Modules on Continuous Polymer Substrates”,D. Grimmer, F. Jeffrey, S. Martens and M. Thomas, J. Solar Energy, 1996,Vol. 18, pages 205-212.

[0037] In order to provide the flexible creases 9 to 12, whichfacilitates closing the modules 2 to 7 at these positions, the modules 2to 7 may be folded along lines XX and then pressed together usingnon-destructive heating to produce permanent flexible creases 9 to 12.

[0038] Referring to FIG. 1, the positions of the lines XX, for theflexible creases 9 to 12 are chosen not to damage the modules 2 to 7,that is, for example, not to lie along electrical interconnecting shunts20 to 25 or bus bars 25 and 28.

[0039] In this embodiment, the lines XX for the flexible creases 9 to 12are positioned equidistant between the shunts 20 to 25, that is a=b anda+b=L. This means that a module length L exists between each part oflines XX.

[0040] In other embodiments it may be found that, to void damage to themodules 2 to 7, a>b or a<b, even so, a+b=L.

[0041] In yet other embodiments of the present invention, where forexample, the device I1 is to be stored in an existing casing which istoo small to accept the full length L of the modules 2 to 7, each lengthL is made a fraction, for example, ⅞ of the length of the module 2 to 7,in this case, the position of each subsequent line XX will be displaced⅛ further back on the module 2 to 7 from the previous one.

[0042] In other embodiments of the present invention, each length Lextends from one module, over at the whole length of at least onefollowing module, to a portion of the next module.

[0043] In FIG. 2, the photovoltaic device 1 is shown electricallyconnected through a diode 30 to energize an article 32, when the modules2 to 7 are exposed to an electrical energy producing form of light byopening the flexible crease 9 to 12 to expose the modules 2 to 7thereto.

[0044] In other embodiments of the present invention, the device 1 whenstored in the retracted form, may be curved to some extent to suit aparticular casing in which it is to be stored. Thus, in these patentspecifications “essentially flat” includes being longitudinally curvedto some extent, but no sufficiently as to be wrapped which could damagethe modules 2 to 7.

[0045] One end of the device 1 may be secured to a casing within whichthe device 1 is to be stored, while the other end of the device 1 may besecured to a removable cover for enclosing the device in the casing.

[0046] The device 1 may be used to charge or recharge a rechargeablestorage cell or battery, such as, for example, those referred to asalkaline, nickel-metal-hydride, lithiumion, aluminum-air,nickel-cadmium, lead-acid, or supercapasitor. It will be appreciatedthat, because the device is not wound round the cell or battery, as inthe prior art, standard sized cells or batteries available over thecounter, may be charged or recharged by devices according to the presentinvention. This is a significant advantage over the devices taught inU.S. Pat. No. 5,605,769, dated Feb. 25, 1997, where, as stated in thepatent specification, the outside diameter of a conventional cell orbattery has to be reduced to accommodate the device wound therearound.

[0047] It will be appreciated that the modules 2 need not be flexiblebecause all that is required is that the creased by sufficientlyflexible and for the panels 14 to 19 to be capable of being foldedtogether in a compact manner.

[0048] The flexible creases are preferably permanent creases becausethis enables the panels to be folded together in a much easier manner.

[0049] If the device 1 is too stiff at the line XX, where the creasesare to be made, then increased flexibility may be imparted to the strip1 at these positions by making weak joints at them. The weak joints maybe made by, for example, thinning the strip 1 at these positions and/orproviding slits in the strip 1 at these positions.

[0050] The flexible creases may set the strip 1 with the creases openedto some extent, as shown in FIG. 2. The creases may then be held sprungor compressed together for storage, provided that strip 1 has enoughstiffness to do this. Thus, the strip 1 may be arranged so that, in therelaxed, open position, the modules are opened sufficiently for exposureto light to be converted to electrical energy.

[0051] In FIG. 4, similar parts to those shown in FIGS. 1 to 3 aredesignated by the same reference numerals, and the previous descriptionis relied upon to describe them

[0052] In FIG. 4, modules 30 to 38 are spaced apart along, and adhereto, a support 39 with exposed portions 40 to 46 of the support 39between the modules 30 to 38. The support 39 has flexible, permanentcreases 48 to 54 in the exposed portions 40 to 46, which spring open toexpose the modules 30 to 38 to light. One end designated 56 of thesupport 39 is secured to a casing, a portion of which is shown anddesignated 58, and within which the device 1 is to be stored in theretracted, compact form. The other end designated 60 of the support 39is secured to a lid, a portion of which is shown and designated 62, forclosing the device 1 in the casing 58.

[0053] In other embodiments of the present invention, where the casing58 is used to store a rechargeable cell or battery, at least a portionof device 1 is to be used in an existing casing that was not designed toaccommodate it.

What is Claimed:
 1. A folding photovoltaic strip device, comprising: a.a plurality of photovoltaic modules, joined to form the strip, andwherein, b. the strip is pleated with transversely extending, flexiblecreases to form a series of panels, whereby, i. with the panels foldedtogether in a concertina-like manner, by means of the creases, thedevice is stored in a retracted, compact form and, ii. with the panelsspread out by means of the creases, the modules can be exposed to lightthat is convertible by the modules to electrical energy.
 2. A deviceaccording to claim 1, wherein the panels are essentially flat.
 3. Adevice according to claim 1, wherein flexible creases are atintermediate positions across modules.
 4. A device according to claim 3,wherein each module is provided with a flexible crease.
 5. A deviceaccording to claim 4, wherein the flexible creases are spaced with atleast one module between each pair of them.
 6. A device according toclaim 4, wherein the creases is spaced equidistant but less than thefull length of a module.
 7. A device according to claim 1, furtherincluding a diode electrically connected to the device and through whichan article may be electrically energized by the device.
 8. A deviceaccording to claim 1, wherein the flexible creases are permanentcreases.
 9. A device according to claim 8, wherein the permanent creasesare open, flexible creases that, in the relaxed state, expose themodules to light, and, the strip has sufficient stiffness between thecreases to be compressed to the retracted, compact form.
 10. A deviceaccording to claim 1, wherein the modules are spaced along, and adhereto, a support with exposed portions of the support between modules,flexible, permanent creases are provided in at least some of the exposedportions of the strip.
 11. A device according to claim 10, wherein thecreases will spring open to expose the modules to light.
 12. A deviceaccording to claim 1, further comprising, a) a casing for the strip, andto which a first end of the strip is attached, and, b) a lid for closingthe strip in the casing, and to which a second end of the strip isattached.